Topic
Code-excited linear prediction
About: Code-excited linear prediction is a research topic. Over the lifetime, 2025 publications have been published within this topic receiving 28633 citations. The topic is also known as: CELP.
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Papers
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23 Sep 1991
Patent•
09 May 2012
TL;DR: The selector as a function of characteristics of the input audio signal, at first and second codebook stage respectively, can be provided to select the order of the time domain CELP codebook and conversion region codebook.
Abstract: A codebook device for use in encoding an input acoustic signal includes first and second codebook stages. The first codebook stage includes one of a time domain CELP codebook and a transform domain codebook. The second codebook stage follows the first codebook stage and includes the other of the time domain CELP codebook and the transform domain codebook. A third codebook stage with an adaptive codebook can be provided before the first codebook stage. A selector can be provided to select the order of the time domain CELP codebook and the transform domain codebook at the first and second codebook stages, respectively, as a function of the characteristics of the input acoustic signal.
05 Jun 2000
TL;DR: A formal listening test shows that, at high channel SNR, the improved performance of the proposed hybrid system versus the purely digital systems is noticeable to the average listener.
Abstract: A joint source-channel coding system for transmitting speech on a bandlimited additive white Gaussian noise (AWGN) channel is presented. The proposed method uses a hybrid of digital and analog modulation techniques. The digital part of the system consists of an FS-1016 CELP speech coder followed by a rate-3/5 parallel concatenated (turbo) error correcting code. The analog part, which transmits the quantization error due to the FS-1016 CELP coder consists of a linear encoder and decoder. The advantage of the proposed system is that it achieves excellent rate-distortion/capacity performance that is common in digital systems while maintaining a "graceful degradation" characteristic that is common in analog systems. Comparisons are made with three purely digital systems and two purely analog systems. A formal listening test shows that, at high channel SNR, the improved performance of the proposed hybrid system versus the purely digital systems is noticeable to the average listener.
Proceedings Article•
26 Jul 2013
TL;DR: By comparing the SNR and MMSE with the linear prediction model, the superiority of the proposed nonlinear bi-directional prediction model is proved.
Abstract: Based on the linear prediction theory, This paper proposes a nonlinear bi-directional prediction model for speech signals. After the data preprocessing, an improved GP is used to construct bi-directional prediction model of each frame. Then by the analysis of these models, the normalized nonlinear bi-directional prediction model is obtained. In the experiments, the DUPSO algorithm is used to optimize the parameters. By comparing the SNR and MMSE with the linear prediction model, the superiority of the proposed nonlinear bi-directional prediction model is proved.